State Analysis And Evaluation Of Turnout Based On Multi-Source Data Analysis And Model Simulation

Turnout,as an important part of track structure,is one of the essential railway equipments which is used to make vehicles to move from one track to or over another.There are still many weak links of track structure in the composition of turnout structure,and its performance is still recognized as one of the important marks reflecting the technical level of railway engineering industry.According to statistics,by 2019,35000 km high-speed railway has been built and operated in China.About eight to nine thousand sets of main line turnouts have been laid,in which those made in China accounts for about 80%,and the overall operation is in good condition.However,structural damage and mechanical failure in turnout area also happen occasionally,which has a negative impact on the comfort of riding and the stability of train operation.And at the same time,it also challenges the railway maintenance work.How to evaluate the operation state of turnout reasonably and to provide scientific guidance for railway maintenance has become an urgent problem in Railway Science.Using the data analysis method of large-scale track detection equipment,the turnout state can be evaluated intelligently and comprehensively,which is helpful to more efficient train track quality inspection and state evaluation.In this Doctoral Dissertation,turnout-vehicle dynamics simulation and data analysis are used synthetically to analyze multi-source detection data and to carry out the evaluation research on the structural state and performance of turnout.On the complicated wheel rail relationship in turnout section,the rolling contact calculation method based on the combination of three-dimensional surface projection,Fourier Transform,and Conjugate Gradient Algorithm was proposed.This method synthetically uses trace method,the method of surface contour projection,and normal vector iterative correction to solve the contact geometry problem of three-dimensional wheel rail profile in turnout section.Based on Boundary Element Theory,Bossinesq and Cerruti formulas for describing the relationship between contact displacement and contact force were solved in frequency domain by using the method of combining Fourier Transform with Conjugate Gradient Algorithm,to obtain the distribution of contact force in wheel rail contact spot.Verified by examples,on the premise of ensuring the accuracy of wheel rail contact force calculation,this method improved the calculation efficiency significantly.And on this basis,the dynamic simulation model of turnout-vehicle system is used to study and clarify the dynamic response characteristics of train in turnout section.On solving the inconsistency between the actual mileage of the railway line and the mileage measured by different inspection systems,a fast correction method of mileage deviation based on Five Point Iteration Method(FPIM)is proposed,and on this basis,the correction models of mileage deviation of inspection data of Track Geometry Measurement(TGM),Vehicle Dynamic Measurement(VDM),as well as the Track Loading Vehicle(TLV)are built,respectively.Verified by an example in which the integrated mileage system cannot work normally,the modified VDM mileage is close to the real mileage and the error is within 3 m.FPIM algorithm can save more than 85% computation time on the premise of ensuring the accuracy of mileage deviation correction compared with the traditional correlation analysis method,providing a practical means for the rapid engineering analysis of the correction of the mileage deviation of a large number of test data.On time-frequency analysis of complex signals of frequency components,an adaptive synchronous compression short-time Fourier transform method based on the Ensemble Empirical Mode Decomposition(EEMD)is proposed.Firstly,EEMD is used to decompose the signal into several Intrinsic Mode Functions(IMF).Then the Short Time Fourier Transform(STFT)was used to solve the Renyi entropy of each IMF,to determine the optimal window length.Finally,the window length is used to perform Synchrosqueezing Short Time Fourier Transform(SSTFT)for each IMF,so as to obtain the time-frequency distribution of each IMF.This method effectively improves the resolution of time-frequency analysis method,so that the signal components in the track detection data with complex and variable frequency components can be clearly presented.Verified by vehicle dynamic response data,the vibration acceleration data of axle box in turnout section can well reflect the high frequency vibration and impact characteristics of typical structures of all welded joints,switch rails,and point rails in the turnout area.The response frequency is mainly distributed at 200-350 Hz,with part of energy distributed in the range of 550-600 Hz.The lateral force of wheel axle can better reflect the lower frequency vibration characteristics of wheel set in different sections such as switch area and frog area.At the same time,compared with the switch area,the wheel set in the frog area will produce a lateral vibration with a relatively higher frequency,the response frequency being distributed in the range of 50-60 Hz,125Hz and 160-180 Hz.In the process of diagnosis and evaluation of turnout rail state,the appropriate inspection data can be selected for analyzing according to the actual problems.On passing performance evaluation of turnout,by comprehensively using of track gauge,gauge on one side,speed,and curvature information to analyze and calculate,the precise positioning of actual point of switch rail and point rail was realized,and the accurate judgment of the orientation of turnout and passing mode(direct/lateral)of the train in the turnout section was achieved.Along with statistical characteristics of dynamic response data of car-body,bogie,and wheel set in turnout section,a comprehensive evaluation method of turnout passing performance based on Turnout Passing Index(TPI)was proposed.Verified by inspection data and field checking,this method can effectively improve the recognition accuracy of defective turnout,providing a scientific reference for maintenance of turnout.On track deformation data measured by TLV,an adaptive signal smoothing method based on multiresolution analysis was proposed,which,on the basis of retaining the medium and long wave components reflecting the structure under the rail,effectively filtered out the high frequency impact components caused by welding joints in the data.Taking the time-frequency analysis of the track stiffness inspection data of typical turnout sections of high-speed ballastless railway,conventional railway,and heavy-haul railway,it was found that the main energy components of track stiffness irregularity inspection data in turnout section of high-speed ballastless railway are distributed in the range of 0.15-2(1/m),among them,the wavelength corresponding to turnout plate was the main one.The main energy components in the track stiffness irregularity inspection data of conventional railway and heavy haul railway were distributed in the range of 0.05-0.4(1/m)and 0.03-0.4(1/m),respectively,speculating that it was mainly caused by the rigidity change of the structure under the rail.On this basis,the Track Stiffness Energy Index(TSEI)was proposed to evaluate the track stiffness state of turnout section including fastener,turnout plate,ballast bed,and other structures.Through the analysis of the inspection data and the verification of on-site feedback defective turnout,TSEI can well reflect the defects related to the under rail structure of turnout section,providing a reliable basis for comprehensive diagnosis of turnout state.